LAUSR

Lignin valorization has risen as a promising pathway to supplant the use of petrochemicals for chemical commodities and fuels. However, the challenges of separating and breaking down lignin from lignocellulosic biomass are the primary barrier for success. Integrated biorefinery systems that incorporate both homogeneous and heterogeneous catalysis for the upgrading of lignin intermediates have emerged as a viable solution. Homogeneous catalysis can perform selective chemistries such as the hydrolysis and dehydration of ester or ether bonds that are more suitable for the pretreatment and fractionation of biomass. Heterogeneous catalysis, however, offers a tunable platform for the conversion of extracted lignin into chemicals, fuels, and materials.Tremendous effort has been invested to elucidate the necessary factors for the valorization of lignin using heterogeneous catalysts, with efforts in exploring more robust methods to drive down costs. Current progress in lignin conversion has fostered numerous advances but understanding the key catalyst design principles is important for advancing the field. This Minireview aims to provide a summary on the fundamental design principles for the selective conversion of lignin using heterogeneous catalysts including the pairing of catalyst metals, supports, and solvents. The review puts a particular focus on the use of bimetallic catalysts on porous supports as a strategy for the selective conversion of lignin. Finally, future research on the valorization of lignin is proposed on the basis of recent progress.